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Evaluation of Non-Conventional Coagulants to Remove Turbidity from Water Full text
2012
Devesa-Rey, R. | Bustos, G. | Cruz, J. M. | Moldes, A. B.
Coagulation and flocculation are basic chemical engineering operations employed to remove suspended solids from water. The growing concern for environmental and ecological issues warrants the use of the biodegradable flocculants in wastewater and industrial effluent treatment. In this work, unconventional coagulant, namely lactic acid, calcium lactate, sodium lactate, and citric acid were studied in comparison with AlCl3, a usual coagulant widely employed to remove water turbidity. It was observed that lactic acid and calcium lactate were able to reduce the water turbidity similarly to AlCl3. This fact can be very interesting because lactic acid salts can be produced by biotechnological process, and contrarily to aluminium salts, they are biodegradable, reducing the risk for human and animal’s health.
Show more [+] Less [-]Development of a Passive Sampler for Monitoring of Carbamate and s-Triazine Pesticides in Surface Waters Full text
2012
Bernal-González, Marisela | Durán-Domínguez-de-Bazúa, Carmen
A new sampling system has been developed for the measurement of time-averaged concentrations (TWA) and diffusion coefficients of organic micropollutants in aquatic environments. The system is based on the diffusion of targeted organic compounds through a rate-limiting membrane and the subsequent accumulation of these species in a bound, hydrophobic solid-phase material. Two separate prototype systems are described. One is suitable for the sampling of carbamates such as carbaryl, carbofuran, 3-hydroxycarbofuran, baygon, propham, clorpropham, and the other one for s-triazines such as atrazine, prometryn, propazine, simazine, terbuthylazine, terbutryn, metribuzin, cyanazine, and metamitron pesticides. The systems use solid-phase material (47-mm C₁₈ Empore disk) as the receiving phase but are fitted with rate-limiting membranes of either polysulfone or polycarbonate. For the two designs investigated, the cumulative uptake of all target analytes was considered over exposure periods of 7 days. The determined sampling rates ranged from 0.1323 to 0.0465 L day⁻¹ with both membranes. The best system was the one with the polysulfone membrane allowing a better cumulative uptake.
Show more [+] Less [-]Arsenic and Heavy Metal Uptake and Accumulation in Native Plant Species from Soils Polluted by Mining Activities Full text
2012
García-Salgado, Sara | García-Casillas, David | Quijano-Nieto, Ma Angeles | Bonilla-Simón, Ma Milagros
Arsenic and Heavy Metal Uptake and Accumulation in Native Plant Species from Soils Polluted by Mining Activities Full text
2012
García-Salgado, Sara | García-Casillas, David | Quijano-Nieto, Ma Angeles | Bonilla-Simón, Ma Milagros
Arsenic and heavy metal (specifically Cd, Cr, Cu, Ni, Pb, and Zn) uptake, translocation, and accumulation in ten native plant species spontaneously growing in soils polluted by mining activities were studied, with a focus on future phytoremediation work in polluted soils. Plant and soil samples were collected in the vicinity of the Mónica mine (NW Madrid, Spain). Soil analysis showed the ability of native plants for growing in soils with high concentration levels of Cd, Cu, Pb, Zn, and especially As. From these elements, the highest percentage of extractable elements was found for Cd and the lowest for Pb. A highly significant correlation was observed between total and extractable element concentrations in soils, except for Cu, indicating that total concentration is the most relevant factor for element mobility in these soils. Extractable elements in soils were better correlated with concentrations in plants than total elements in soils; thus, extraction methods applied are suitable to estimate the element phytoavailable fraction in soils, which depends on the plant species and not only on the element mobility in soils. High element concentrations were found in the aboveground parts of Corrigiola telephiifolia (As and Pb), Jasione montana (Cd and Zn), and Digitalis thapsi (As, Cd, Cu, Pb and Zn). However, considering the translocation and accumulation factors, together with the concentration levels found in roots and aboveground parts, only C. telephiifolia could be considered a Pb accumulator and an As hyperaccumulator plant, which could be used for future phytoremediation work in soils polluted with As.
Show more [+] Less [-]Arsenic and heavy metal uptake and accumulation in native plant species from soils polluted by mining activities Full text
2012
García Salgado, Sara | Garcia Casillas, David | Quijano Nieto, M. Angeles | Bonilla Simon, M. Milagros
Arsenic and heavy metal (specifically Cd, Cr, Cu, Ni, Pb, and Zn) uptake, translocation, and accumulation in ten native plant species spontaneously growing in soils polluted by mining activities were studied, with a focus on future phytoremediation work in polluted soils. Plant and soil samples were collected in the vicinity of the Mónica mine (NW Madrid, Spain). Soil analysis showed the ability of native plants for growing in soils with high concentration levels of Cd, Cu, Pb, Zn, and especially As. From these elements, the highest percentage of extractable elements was found for Cd and the lowest for Pb. A highly significant correlation was observed between total and extractable element concentrations in soils, except for Cu, indicating that total concentration is the most relevant factor for element mobility in these soils. Extractable elements in soils were better correlated with concentrations in plants than total elements in soils; thus, extraction methods applied are suitable to estimate the element phytoavailable fraction in soils, which depends on the plant species and not only on the element mobility in soils. High element concentrations were found in the aboveground parts of Corrigiola telephiifolia (As and Pb), Jasione montana (Cd and Zn), and Digitalis thapsi (As, Cd, Cu, Pb and Zn). However, considering the translocation and accumulation factors, together with the concentration levels found in roots and aboveground parts, only C. telephiifolia could be considered a Pb accumulator and an As hyperaccumulator plant, which could be used for future phytoremediation work in soils polluted with As.
Show more [+] Less [-]Reducing NO₂ Pollution over Urban Areas: Air Quality Modelling as a Fundamental Management Tool Full text
2012
Reducing NO₂ Pollution over Urban Areas: Air Quality Modelling as a Fundamental Management Tool Full text
2012
Recently, specific air quality problems have been detected in the northern region of Portugal. The nitrogen oxide (NO₂) annual limit value has been surpassed at several air quality monitoring stations in the northern region, and according to European legislation, air quality plans must be designed and implemented to reduce those levels. The analysis of the air quality data from the stations concerning NO₂ exceedances indicates that traffic is responsible for an increase of more than 40 % compared with the urban background value. Specific measures to reduce NOx emissions have been selected and are related not only mainly to the traffic sector but also to the industrial and residential combustion sectors. The main objective of this study is to investigate the impact of the selected measures on the ambient levels of NO₂ in northern Portugal using a numerical modelling tool—The Air Pollution Model (TAPM). TAPM was applied over the study region using a 120 × 120-km² simulation domain and a spatial resolution of 4.8 × 4.8 km². The entire year of 2010 was simulated and was set as the base year to analyse the impact of the selected measures. Two scenarios have been defined and simulated: the base situation, which considers current NOx emissions, and the reduction scenario for which NOx emissions were re-estimated considering the implementation of the measures. The modelling results demonstrate a decrease of 4–5 μg m⁻³ in the annual NO₂ levels in the study region. Moreover, the implementation of the selected measures will allow compliance with the NO₂ annual limit values in three of the five air quality stations that measured levels surpassing those established by legislation. This situation demands additional measures that should be implemented at the local level and that particularly focus on the traffic sector.
Show more [+] Less [-]Reducing NO2 pollution over urban areas: air quality modelling as a fundamental management tool Full text
2012
Borrego, C. | Monteiro, A. | Sá, E. | Carvalho, A. | Coelho, D. | Dias, D. | Miranda, A. I.
Recently, specific air quality problems have been detected in the northern region of Portugal. The nitrogen oxide (NO2) annual limit value has been surpassed at several air quality monitoring stations in the northern region, and according to European legislation, air quality plans must be designed and implemented to reduce those levels. The analysis of the air quality data from the stations concerning NO2 exceedances indicates that traffic is responsible for an increase of more than 40 % compared with the urban background value. Specific measures to reduce NOx emissions have been selected and are related not only mainly to the traffic sector but also to the industrial and residential combustion sectors. The main objective of this study is to investigate the impact of the selected measures on the ambient levels of NO2 in northern Portugal using a numerical modelling tool— The Air Pollution Model (TAPM). TAPM was applied overthestudyregionusinga120×120-km2 simulation domain and a spatial resolution of 4.8×4.8 km2. The entire year of 2010 was simulated and was set as the base year to analyse the impact of the selected measures. Two scenarios have been defined and simulated: the base situation, which considers current NOx emissions, and the reduction scenario for which NOx emissions were re-estimated considering the implementation ofthe measures. Themodelling results demonstrate a decrease of 4–5 μgm−3 in the annual NO2 levels in the study region. Moreover, the implementation of the selected measures will allow compliance with the NO2 annual limit values in three of the five air quality stations that measured levels surpassing those established by legislation. This situation demands additional measures that should be implemented at the local level and that particularly focus on the traffic sector. | published
Show more [+] Less [-]Evaluating a Rapid Method to Determine Faecal Burden on Pasture from Grazing Cattle Full text
2012
Oliver, David M. | Young, Grant
Evaluating a Rapid Method to Determine Faecal Burden on Pasture from Grazing Cattle Full text
2012
Oliver, David M. | Young, Grant
Grazing livestock excrete large volumes of faecal material on pasture. Understanding the magnitude of this faecal burden is important for attributing sources of agricultural pollutants to different spatial and temporal scales. This field-based study evaluated the utility and transferability of a rapid approach often used in plant ecology (the line intercept method (LIM)) for estimating faecal burden from grazing cattle on pasture. Results from the LIM were of equivalent magnitude, with no significant difference observed, to those derived from more time-consuming sampling of faecal material from pasture using a quadrat-style methodology (herein termed burden sampling). However, the variability in estimates using the LIM was much larger (839–7,079 kg fresh weight faeces over the 50,000 m² field) compared with estimates provided by the burden sampling of pasture at 0.2 % area sampled (1,616–3,979 kg/50,000 m²), 0.4 % area sampled (1,753–2,723 kg/50,000 m²) and 0.8 % area sampled (1,212–2,344 kg/50,000 m²). The LIM offers a rapid and cost-effective alternative to time-consuming sampling campaigns of faecal burden on pasture and provides estimations that are preferable to back-of-the-envelope calculations based on the over-simplification of livestock excretion rates.
Show more [+] Less [-]Evaluating a Rapid Method to Determine Faecal Burden on Pasture from Grazing Cattle Full text
2012
Oliver, David | Young, Grant | Biological and Environmental Sciences | University of Stirling | 0000-0002-6200-562X
Grazing livestock excrete large volumes of faecal material on pasture. Understanding the magnitude of this faecal burden is important for attributing sources of agricultural pollutants to different spatial and temporal scales. This field-based study evaluated the utility and transferability of a rapid approach often used in plant ecology (the line intercept method (LIM)) for estimating faecal burden from grazing cattle on pasture. Results from the LIM were of equivalent magnitude, with no significant difference observed, to those derived from more time-consuming sampling of faecal material from pasture using a quadrat-style methodology (herein termed burden sampling). However, the variability in estimates using the LIM was much larger (839-7,079 kg fresh weight faeces over the 50,000 m2 field) compared with estimates provided by the burden sampling of pasture at 0.2 % area sampled (1,616-3,979 kg/50,000 m2), 0.4 % area sampled (1,753-2,723 kg/50,000 m2) and 0.8 % area sampled (1,212-2,344 kg/50,000 m2). The LIM offers a rapid and cost-effective alternative to time-consuming sampling campaigns of faecal burden on pasture and provides estimations that are preferable to back-of-the-envelope calculations based on the over-simplification of livestock excretion rates.
Show more [+] Less [-]Lichens Used as Monitors of Atmospheric Pollution Around Agadir (Southwestern Morocco)—A Case Study Predating Lead-Free Gasoline Full text
2012
Monna, Fabrice | Bouchaou, Lhoussaine | Rambeau, Claire | Losno, Rémi | Bruguier, Olivier | DongarrÃ, Gaetano | Black, Stuart | Chateau, Carmela
Lichens Used as Monitors of Atmospheric Pollution Around Agadir (Southwestern Morocco)—A Case Study Predating Lead-Free Gasoline Full text
2012
Monna, Fabrice | Bouchaou, Lhoussaine | Rambeau, Claire | Losno, Rémi | Bruguier, Olivier | DongarrÃ, Gaetano | Black, Stuart | Chateau, Carmela
More than 30 epiphytic lichens, collected in Agadir (Morroco) and along a 150-km transect from the Atlantic Ocean eastward, were analyzed for their metal content and lead isotopic composition. This dataset was used to evaluate atmospheric metal contamination and the impact of the city on the surrounding area. The concentrations of Cu, Pb, and Zn (averageâ±â1 SD) were 20.9â±â15.2 μg g−1, 13.8â±â9.0 μg g−1, and 56.6â±â26.6 μg g−1, respectively, with the highest values observed in lichens collected within the urban area. The 206Pb/207Pb and 208Pb/207Pb ratios in the lichens varied from 1.146 to 1.186 and from 2.423 to 2.460, respectively. Alkyllead-gasoline sold in Morocco by the major petrol companies gave isotopic ratios of 206Pb/207Pbâ=â1.076–1.081 and 208Pb/207Pbâ=â2.348–2.360. These new, homogeneous values for gasoline-derived lead improve and update the scarce isotopic database of potential lead sources in Morocco, and may be of great value to future environmental surveys on the presence of lead in natural reservoirs, where it persists over time (e.g., soils and sediments). The interest of normalizing metal concentrations in lichens to concentrations of a lithogenic element is demonstrated by the consistency of the results thus obtained with lead isotopic ratios. Leaded gasoline contributed less than 50% of the total amount of lead accumulated in lichens, even in areas subject to high vehicular traffic. This strongly suggests that the recent banishment of leaded gasoline in Morocco will not trigger a drastic improvement in air quality, at least in Agadir.
Show more [+] Less [-]Lichens used as monitors of atmospheric pollution around Agadir (Southwestern Morocco) - a case study predating lead-free gasoline Full text
2012
Monna, F | Bouchaou, L | Rambeau, Claire | Losno, R | Bruguier, O | Dongarra, G | Black, Stuart | Chateau, C
More than 30 epiphytic lichens, collected in Agadir (Morroco) and along a 150-km transect from the Atlantic Ocean eastward, were analyzed for their metal content and lead isotopic composition. This dataset was used to evaluate atmospheric metal contamination and the impact of the city on the surrounding area. The concentrations of Cu, Pb, and Zn (average ± 1 SD) were 20.9 ± 15.2 μg g−1, 13.8 ± 9.0 μg g−1, and 56.6 ± 26.6 μg g−1, respectively, with the highest values observed in lichens collected within the urban area. The 206Pb/207Pb and 208Pb/207Pb ratios in the lichens varied from 1.146 to 1.186 and from 2.423 to 2.460, respectively. Alkyllead-gasoline sold in Morocco by the major petrol companies gave isotopic ratios of 206Pb/207Pb = 1.076–1.081 and 208Pb/207Pb = 2.348–2.360. These new, homogeneous values for gasoline-derived lead improve and update the scarce isotopic database of potential lead sources in Morocco, and may be of great value to future environmental surveys on the presence of lead in natural reservoirs, where it persists over time (e.g., soils and sediments). The interest of normalizing metal concentrations in lichens to concentrations of a lithogenic element is demonstrated by the consistency of the results thus obtained with lead isotopic ratios. Leaded gasoline contributed less than 50% of the total amount of lead accumulated in lichens, even in areas subject to high vehicular traffic. This strongly suggests that the recent banishment of leaded gasoline in Morocco will not trigger a drastic improvement in air quality, at least in Agadir.
Show more [+] Less [-]Seawater carbonate chemistry and copepod Centropages tenuiremis feeding, filtering and respiration rate during experiments, 2012 Full text
2012
Li, Wei | Gao, Kunshan
Seawater carbonate chemistry and copepod Centropages tenuiremis feeding, filtering and respiration rate during experiments, 2012 Full text
2012
Li, Wei | Gao, Kunshan
Climate change mediates marine chemical and physical environments and therefore influences marine organisms. While increasing atmospheric CO2 level and associated ocean acidification has been predicted to stimulate marine primary productivity and may affect community structure, the processes that impact food chain and biological CO2 pump are less documented. We hypothesized that copepods, as the secondary marine producer, may respond to future changes in seawater carbonate chemistry associated with ocean acidification due to increasing atmospheric CO2 concentration. Here, we show that the copepod, Centropages tenuiremis, was able to perceive the chemical changes in seawater induced under elevated CO2 concentration (>1700 µatm, pH < 7.60) with avoidance strategy. The copepod's respiration increased at the elevated CO2 (1000 µatm), associated acidity (pH 7.83) and its feeding rates also increased correspondingly, except for the initial acclimating period, when it fed less. Our results imply that marine secondary producers increase their respiration and feeding rate in response to ocean acidification to balance the energy cost against increased acidity and CO2 concentration.
Show more [+] Less [-]A marine secondary producer respires and feeds more in a high CO₂ ocean Full text
2012
Li, Wei | Gao, Kunshan
Climate change mediates marine chemical and physical environments and therefore influences marine organisms. While increasing atmospheric CO₂ level and associated ocean acidification has been predicted to stimulate marine primary productivity and may affect community structure, the processes that impact food chain and biological CO₂ pump are less documented. We hypothesized that copepods, as the secondary marine producer, may respond to future changes in seawater carbonate chemistry associated with ocean acidification due to increasing atmospheric CO₂ concentration. Here, we show that the copepod, Centropages tenuiremis, was able to perceive the chemical changes in seawater induced under elevated CO₂ concentration (>1700μatm, pH<7.60) with avoidance strategy. The copepod’s respiration increased at the elevated CO₂ (1000μatm), associated acidity (pH 7.83) and its feeding rates also increased correspondingly, except for the initial acclimating period, when it fed less. Our results imply that marine secondary producers increase their respiration and feeding rate in response to ocean acidification to balance the energy cost against increased acidity and CO₂ concentration.
Show more [+] Less [-]Predicting regional space–time variation of PM2.5 with land-use regression model and MODIS data Full text
2012
Mao, Liang | Qiu, Youliang | Kusano, Claudia | Xu, Xiaohui
PURPOSE: Existing land-use regression (LUR) models use land use/cover, population, and traffic information to predict long-term intra-urban variation of air pollution. These models are limited to explaining spatial variation of air pollutants, and few of them are capable of addressing temporal variability. This article proposes a space–time LUR model at a regional scale by incorporating aerosol optical depth (AOD) data from the Moderate Resolution Imaging Spectroradiometer (MODIS). METHODS: A multivariate regression model was established to predict the distribution of particle matters less than 2.5 μm in aerodynamic diameter (PM2.5) in Florida, USA. Monthly PM2.5 averages at 34 monitoring sites in the year 2005 were used as the dependent variable, while independent variables include land-use patterns, population, traffic, and topographic characteristics. In addition, a monthly AOD variable derived from the MODIS data was integrated into the regression as a space–time predictor. Cross-validation procedures were conducted to validate this AOD-enhanced LUR model. RESULTS: The final regression model yields a coefficient of determination (R 2) of 0.63, which is comparable to other studies that employ aerodynamic/meteorological models. The cross validation indicated a good agreement between the observed and predicted PM2.5 with a mean residual of 0.02 μg/m3. The distance to heavy-traffic roads is negatively associated with the concentrations of PM2.5, while agricultural land use is positively correlated. PM2.5 tends to concentrate in high-latitude areas of Florida and during summer/fall seasons. The monthly AOD has a significant contribution to explaining the variation of PM2.5 and remarkably enhances the model performance. CONCLUSIONS: This research is the first attempt to improve current LUR models by integrating remote sensing technologies. The integrative model approach offers an effective means to estimate air pollution over time and space, and could be an alternative to the classic meteorological approach. The model results would provide adequate measurements for epidemiological studies, particularly for chronic health effects in large populations.
Show more [+] Less [-]Isolation of a novel Pseudomonas sp from soil that can efficiently degrade polyethylene succinate Full text
2012
Tribedi, Prosun | Sarkar, Subhasis | Mukherjee, Koushik | Sil, Alok K.
PURPOSE: Polyethylene succinate (PES) is a biodegradable synthetic polymer and therefore widely used as a base material in plastic industry to circumvent the environmental problems related with the non-biodegradability of other polymers like polyethylene. Till date only few organisms have been reported to have the ability to degrade PES. Therefore for better management of PES-related environmental waste, the present study is targeted towards isolating mesophilic organism(s) capable of more efficient degradation of PES. RESULTS: Strain AKS2 was isolated from soil based on survival on a selection plate wherein PES was used as sole carbon source. Ribotyping and biochemical tests revealed that AKS2 is a new strain of Pseudomonas. Scanning electron and atomic force microscopic analysis of the PES films obtained after incubation with AKS2 confirmed PES-degradation ability of AKS2, wherein an alteration in surface topology was observed. The kinetics of PES weight loss showed that AKS2 degrades PES maximally during its logarithmic growth phase at a rate of 1.65 mg/day. This degradation is mediated by esterase activity and may also involve cell-surface hydrophobicity. It has also been observed that AKS2 is able to degrade PES considerably even in the presence of glucose, which is likely to increase the bioremediation potential of this isolate. CONCLUSION: A new strain of Pseudomonas has been isolated from soil that is able to adhere to PES and degrade this polymer efficiently. This organism has the potential to be implemented as a useful tool for bioremediation of PES-derived materials.
Show more [+] Less [-]Acute and chronic toxicity of benzotriazoles to aquatic organisms Full text
2012
Seeland, Anne | Oetken, Matthias | Kiss, Aliz | Fries, Elke | Oehlmann, Jörg
PURPOSE: Resulting from their intensive use as corrosion inhibitors in aircraft deicing and anti-icing fluids (ADAF) and for silver protection in dishwasher detergents benzotriazoles (BTs) are widespread in European surface waters. The current study aimed on an ecotoxicological characterization of 1H-benzotriazole (1H-BT) and 5-methyl-1H-benzotriazole (5MBT). METHODS: Acute and chronic OECD guideline tests were conducted with primary producers (Desmodesmus subspicatus, Lemna minor) and two daphnia species (Daphnia magna, Daphnia galeata) to characterize the hazard of these chemicals. Additionally, the estrogenic activity of both BTs was analyzed in vitro using a recombinant yeast estrogen screen (YES). RESULTS: Both BTs revealed significant effects in acute and chronic experiments, but exhibited no estrogenic activity in the YES. The algal growth test displayed an inhibited cell number increase with effect concentration (EC) values of EC10 1.18 and 2.86 mg l-1 for 1H-BT and 5MBT, respectively. In the Lemna test, EC10 values were 3.94 mg l-1 (1H-BT) and 2.11 mg l-1 (5MBT). D. magna was also affected with EC50 (48 h) values of 107 mg l-1 for 1H-BT and 51.6 mg l-1 for 5MBT. D. galeata was more sensitive with an EC50 (48 h) of 14.7 mg 1H-BT l-1 and 8.13 mg 5MBT l-1. In the 21-day reproduction tests with D. magna, the EC10 for 5MBT was 5.93 mg l-1 while 1H-BT showed no adverse effects. D. galeata turned out to be more sensitive in the chronic study with EC10 values of 0.97 mg l-1 for 1H-BT and 0.40 mg l-1 for 5 MBT. CONCLUSION: Because BTs are regularly found in the aquatic environment at lower μg l-1 concentrations reflecting their persistence and poor elimination during wastewater treatment processes, a preliminary risk assessment was conducted. There is little indication that BTs pose a risk for aquatic ecosystems at current exposure levels during most of the year. However, it cannot be excluded that in winter with a higher usage of ADAFs environmental concentrations may well exceed the level that is considered safe for aquatic organisms.
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